Abstract: 【Objective】To study the effects of different periods of selenium fertilization on the agronomic traits and yield of broomcorn millet in Ordos City,Inner Mongolia,and optimize the production technology of selenium-enriched broomcorn millet in this area.【Methods】Two main varieties of local broomcorn millet,Yimi No. 11 and Yishu No. 11 were used as experimental materials to spray commercial selenium-enriched fertilizer on the leaf surface of broomcorn millet at jointing stage and filling stage. The variance and interaction effects of different selenium fertilizer treatments were analyzed for agronomic traits,yield and grain selenium content of broomcorn millet.【Results】Spraying selenium fertilizer was beneficial to the increase of 1 000-grain weight of broomcorn millet,and the results showed that the filling stage（A0B1）>filling stage+jointing stage （A1B1）>jointing stage（A1B0）. After spraying selenium fertilizer at filling stage+ joniting stage,the yield and grain selenium content of Yimi No. 11 increased more than Yishu No. 11,the yield of Yimi No. 11 increased by 17.85%,i. e. 6 371.17 kg/hm²,while the yield of Yishu No. 11 increased by 8.06%,i. e. 6 142.28 kg/hm². After spraying selenium fertilizer at filling stage+joining stage,the highest selenium content of Yimi No. 11 and Yishu No. 11 grains was 1.167 mg/kg and 0.756 mg/kg,respectively,which extremely significant increased the grain selenium content compared with other treatments（P<0.01）.【Conclusion】Spraying selenium fertilizer can increase the yield of broomcorn millet,and the best spraying effect is at filling stage+jointing stage. Yimi No. 11 is more suitable for selenium fertilizer application. Applying selenium fertilizer at both grain filling stage and jointing stage can give both high yield and rich selenium.

Key words: Broomcorn millet, Selenium fertilizer, Agronomic traits, Yield, Grain selenium content